What biomarker is increased in eosinophilic asthma and can be readily measured?

In eosinophilic asthma, exhaled nitric oxide (eNO) is significantly increased and is a valuable biomarker that reflects airway inflammation, particularly from eosinophils. The measurement of eNO is a non-invasive procedure that indicates the presence of eosinophilic inflammation in the airways, which is a hallmark of this type of asthma. Elevated levels of eNO can be correlated with the severity of asthma and can also help guide treatment decisions, making it a useful tool for monitoring and managing patients with eosinophilic asthma.

Other potential biomarkers, such as blood eosinophils or serum IgE levels, can provide helpful information as well; however, their measurements are not as direct or immediate in assessing airway inflammation compared to eNO. Blood eosinophils offer a systemic view but do not specifically indicate airway status. Serum IgE levels can be indicative of atopy and allergic responses but are not specific to eosinophilic asthma alone. Exhaled carbon dioxide is not a recognized biomarker of eosinophilic inflammation and is more related to ventilation status.